The shell+perl "[de]packetize()" helper functions were added in
4414a15002 (t/lib-git-daemon: add network-protocol helpers,
2018-01-24), and around the same time we added the "pkt-line" helper
in 74e7002961 (test-pkt-line: introduce a packet-line test helper,
2018-03-14).
For some reason it seems we've mostly used the shell+perl version
instead of the helper since then. There were discussions around
88124ab263 (test-lib-functions: make packetize() more efficient,
2020-03-27) and cacae4329f (test-lib-functions: simplify packetize()
stdin code, 2020-03-29) to improve them and make them more efficient.
There was one good reason to do so, we needed an equivalent of
"test-tool pkt-line pack", but that command wasn't capable of handling
input with "\n" (a feature) or "\0" (just because it happens to be
printf-based under the hood).
Let's add a "pkt-line-raw" helper for that, and expose is at a
packetize_raw() to go with the existing packetize() on the shell
level, this gives us the smallest amount of change to the tests
themselves.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We pass "sideband: " as our identity for errors to recv_sideband(). But
it already adds the trailing colon and space. This doesn't invalidate
any tests, but it looks funny when you examine the test output.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 2b695ecd74 (t5500: count objects through stderr, not trace,
2020-05-06) we tried to ensure that the "Total 3" message could be
grepped in Git's output, even if it sometimes got chopped up into
multiple lines in the trace machinery.
However, the first instance where this mattered now goes through the
sideband machinery, where it is _still_ possible for messages to get
chopped up: it *is* possible for the standard error stream to be sent
byte-for-byte and hence it can be easily interrupted. Meaning: it is
possible for the single line that we're looking for to be chopped up
into multiple sideband packets, with a primary packet being delivered
between them.
This seems to happen occasionally in the `vs-test` part of our CI
builds, i.e. with binaries built using Visual C, but not when building
with GCC or clang; The symptom is that t5500.43 fails to find a line
matching `remote: Total 3` in the `log` file, which ends in something
along these lines:
remote: Tota
remote: l 3 (delta 0), reused 0 (delta 0), pack-reused 0
This should not happen, though: we have code in `demultiplex_sideband()`
_specifically_ to stitch back together lines that were delivered in
separate sideband packets.
However, this stitching was broken in a subtle way in fbd76cd450
(sideband: reverse its dependency on pkt-line, 2019-01-16): before that
change, incomplete sideband lines would not be flushed upon receiving a
primary packet, but after that patch, they would be.
The subtleness of this bug comes from the fact that it is easy to get
confused by the ambiguous meaning of the `break` keyword: after writing
the primary packet contents, the `break;` in the original version of
`recv_sideband()` does _not_ break out of the `while` loop, but instead
only ends the `switch` case:
while (!retval) {
[...]
switch (band) {
[...]
case 1:
/* Write the contents of the primary packet */
write_or_die(out, buf + 1, len);
/* Here, we do *not* break out of the loop, `retval` is unchanged */
break;
[...]
}
if (outbuf.len) {
/* Write any remaining sideband messages lacking a trailing LF */
strbuf_addch(&outbuf, '\n');
xwrite(2, outbuf.buf, outbuf.len);
}
In contrast, after fbd76cd450 (sideband: reverse its dependency on
pkt-line, 2019-01-16), the body of the `while` loop was extracted into
`demultiplex_sideband()`, crucially _including_ the logic to write
incomplete sideband messages:
switch (band) {
[...]
case 1:
*sideband_type = SIDEBAND_PRIMARY;
/* This does not break out of the loop: the loop is in the caller */
break;
[...]
}
cleanup:
[...]
/* This logic is now no longer _outside_ the loop but _inside_ */
if (scratch->len) {
strbuf_addch(scratch, '\n');
xwrite(2, scratch->buf, scratch->len);
}
The correct way to fix this is to return from `demultiplex_sideband()`
early. The caller will then write out the contents of the primary packet
and continue looping. The `scratch` buffer for incomplete sideband
messages is owned by that caller, and will continue to accumulate the
remainder(s) of those messages. The loop will only end once
`demultiplex_sideband()` returned non-zero _and_ did not indicate a
primary packet, which is the case only when we hit the `cleanup:` path,
in which we take care of flushing any unfinished sideband messages and
release the `scratch` buffer.
To ensure that this does not get broken again, we introduce a pair of
subcommands of the `pkt-line` test helper that specifically chop up the
sideband message and squeeze a primary packet into the middle.
Final note: The other test case touched by 2b695ecd74 (t5500: count
objects through stderr, not trace, 2020-05-06) is not affected by this
issue because the sideband machinery is not involved there.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In a future commit, we will use PACKET_READ_RESPONSE_END to separate
messages proxied by remote-curl. To prepare for this, add the
PACKET_READ_RESPONSE_END enum value.
In switch statements that need a case added, die() or BUG() when a
PACKET_READ_RESPONSE_END is unexpected. Otherwise, mirror how
PACKET_READ_DELIM is implemented (especially in cases where packets are
being forwarded).
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
busybox's sed isn't binary clean.
Thus, triggers false-negative on this test.
We could replace sed with perl on this usecase.
But, we could slightly modify the helper to discard unwanted data in the
beginning.
Fix the false negative by updating this helper.
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add an 'unpack-sideband' subcommand to the test-pkt-line helper to
enable unpacking packet line data sent multiplexed using a sideband.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Introduce a packet-line test helper which can either pack or unpack an
input stream into packet-lines and writes out the result to stdout.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
